Roll of thermoplastic material and method for dispensing same



April 23, 1963 H. o. CORBETT 3,086,648

ROLL OF THERMOPLASTIC MATERIAL AND METHOD FOR DISPENSING SAME Filed May 4, 1961 INVENTOR HERBERT CORBETT ATTORNEY United States Patent Ofitice 3,086,648 Patented Apr. 23, 1963 3,986,648 RGLL F THERMOPLASTIC MATERIAL AND NLETHGD FOR DISPENSING SAME Herbert G. Corbett, Canandaigua, N.Y., assignor to National Distillers and Chemical Corporation, New York,

N.Y., a corperation of Virginia Filed May 4, 1961, Ser. No. 107,743 5 Claims. (1. 206-59) This invention relates to a novel method for dispensing sheet wrapping material in predetermined lengths and to novel methods and apparatus for the production of rolls of such material.

More particularly, the invention is concerned with the production of rolls of elastomeric, thermoplastic materials of extremely thin gauge and having severely high and inherent clinging characteristics, such rolls being prefabricated in a novel manner whereby predetermined lengths of material may be successively detached therefrom with particular convenience. Exemplary materials may be identified as polyolefins, and copolymers, including polypropylene, polyethylene, Saran wrap, and the like, having a thickness on the order of .00025 to .0015 inch.

Sheet material of this character has extremely high cling characteristics and, when wound in rolled form, the unrolling thereof provides problems by reason of the free edge clinging to the remainder of the roll and being extremely diificult to grasp. This difiiculty is overcome in part, in the prior art, by merchandising rolls of such material in dispensing containers where the free extremity of the material passes through a dispensing aperture, usualy provided by the depending front lip of the top of the receptacle and the adjacent container wall, and severance is accomplished (generally along a mechanical cutting edge) at a point remote from the mouth of the aperture whereby the extremity of the rolled material is maintained in spaced relationship from the roll per se and thus prevented from returning and clinging thereto.

It has been unknown, heretofore, to produce rolls of such sheet material, which may be substantially devoid of slip characteristics, so prefabricated that predetermined and substantially uniform lengths may be detached therefrom, automatically and with particular case,

Accordingly, it is a major object of the present invention to provide a novel method for dispensing successive predetermined lengths of elastomeric, thermoplastic sheet material of the character with which we here are concerned, from a prefabricated roll thereof.

It is a further object of the invention to provide a novel roll of elastomeric thermoplastic sheet material of the character contemplated from which successive, substantially uniform predetermined lengths may be dispensed.

It is a still further object of the present invention to provide novel apparatus for the production of rolls of sheet material of the character with which we here are concerned from which successive, substantially uniform predetermined lengths may be dispensed.

It is a further object of the invention to provide a novel method for dispensing successive lengths of sheet material from a roll't e eo w ere t e ch ng of o e length will res lt in t e uft ng o t r e of the edge of the next adjacent length so that said corners will extend outwardly from the remainder of the roll, for convenient grasping and ready dispensing of the successive length.

Further objects and advantages of the invention will be readily apparent from the following description, taken in conjunction with the accompanying drawing wherein:

FIGURE 1 is a side elevational view of a roll of material of the character with which we here are concerned, wound upon a suitable core;

FIGURE 2 is a side elevational view, similar to FIG- URE l and with parts broken away, illustrating one form of cutting means whereby the rolled material may be partially slit for subsequent severance into predetermined lengths;

FIGURE 3 is a transverse sectional view taken on the line 33 of FIGURE 2;

FIGURE 4 is a transverse sectional view, somewhat similar to FIGURE 3, illustrating a slightly different slitting operation; and

FIGURE 5 is a perspective View illustrating, somewhat diagrammatically, the novel method of dispensing or severance of one length of material and the automatic and simultaneous tufting of the corners of the free edge of the next successive length.

As shown in the drawing, a continuous length of elastomeric, thermoplastic sheet material of film 10 is Wound upon a suitable core 11 in any desired manner as is well known in this art. This film which, as stated hereabove, may have a thickness on the order of .00025 to .0015 inch, may be produced in any desired manner as, for example, by extrusion or casting and may be of any desired or required width. The core 11, which may be a throw-away item produced from paper or cardboard or may be a salvageable article, should be of sufiicient rigidity to sustain the roll of film, and is of a carefully selected diameter having strict relationship to and control over the predetermined lengths of sheet material to be dispensed from said roll as will be explained more fully hereafter.

It should be understood that the diameters of cores employed may vary as desired, without limit insofar as operativeness of the invention is concerned, the core diameter being critical only in connection with the determination of the substantially uniform successive lengths to be dispensed therefrom. So, too, with the length of the core and the width of the film as well as the quantity of film to be wound upon any single roll, there being wide latitude in connection with these latter factors and in strict accordance with given requirements or commercial considerations.

After a finished roll of elastomeric film is produced, with the desired quantity or convolutions of film thereon, suitable means is provided for cutting or slitting said film through to the core, this slit being in a direction transverse to the length of the film and parallel to the axis of the core. This slit may be accomplished by a cutting knife, a fine cut or slit being made across the film except for a distance of approximately /8" on each edge.

As shown more particularly in FIGURE 2 of the drawing, during the cutting or slitting operation the core 11 may be retained upon suitable adjustable mandrels 12 and a circular rotating knife blade 13, mounted upon a shaft 14 and driven in any desired manner, may be employed for cutting the slit 15 through the rolled film leaving unseverecl portions 15a at each extremity, The roll of film may be retained against lateral movement and mechanism provided for advancing the rotating knife blade longitudinally of the film until the requisite slit, which preferably extends through all of the convolutions of the film, is completed,

Alternatively, the rotating knife blade 13 may be supported upon a fixed axis and the roll of film may be mounted for longitudinal movement either below or above the cutting edge. Lathe-like mechanism may be provided, modified to meet the requirements stated hereabove, with requisite adjustability as between film roll and knife edge to insure the accuracy of the depth and length of the cut.

Where the coreis of relatively small diameter, a smaller knife blade may be employed; with larger cores, and the possibility of a substantially increased number of film convolutions, larger cutting knives may be utilized.

If desired, a vertically reciprocable knife blade may be employed, the length of the blade being such as to provide a slit or cut of the length required. It has been found in practice that a rotating knife blade, rotating in a single direction, has the inherent advantage, when rotating and cutting through multiple layers of film, of imparting a spinning effect in an outward direction to the cut edges resulting in an ease of subsequent separation as successive lengths of film are detached.

As illustrated in FIGURES 2 and 3 of the drawings, the adjustment between the rotating knife blade 13 and the core 11 is such that the knife edge does not penetrate into the core any appreciable distance. However, as shown in FIGURE 4, the adjustment may be such that the knife blade 13 makes a complete cut not only through the layers of film, except for the unsevered edge portions 15a, but also through the core 11 as indicated at 11a.

With the cut extending through each convolution of film, except for a distance approximating on each edge, the predetermined length of each successive piece of material to be dispensed or detached from the roll will approximate the circumference of the core, each such length increasing minutely with each convolution of this variance being immaterial insofar as end use or commercial considerations are concerned. For example, with a core having a diameter of 2", the length of the innermost piece of material to be dispensed will be pi 2" (3.14159265X2") or slightly in excess of 6%". Thus, in each case, the diameter of the core employed will control the lengths of film dispensed therefrom.

It has been discovered that when a single length of thermoplastic film is detached from a roll thereof which has been produced in accordance with the teachings of the present invention, the physical tearing of the uncut edge portions 15a produces what may be termed a slight stretching and distortion thereof, creating upstanding or tufted corners 15b which extend outwardly from the roll per se as is illustrated clearly in FIGURE of the drawing. These tufted corners provide ready means for grasping the next successive length of film and a similar phenomenon occurs as each length is detached.

There has just been described novelmethods for manufacturing rolls of elastomeric, thermoplastic materials, which may be of thin gauge and have high clinging characteristics, and novel methods for dispensing such materials, successively and in predetermined lengths from such rolls, each such length having direct relationship to the diameter of the core upon which the material is wound.

It also is contemplated, within the present inventive concept, that cores of sufiiciently large diameters may be employed whereby more than a single slit may be cut through the convolutions of film wound thereon. As a single example, with a core having a 6" diameter, diametrically opposed slits may be provided, in which event the length of each successive sheet detached therefrom will be slightly less than 9 /2.

It will be obvious to those skilled in this art that various other changes may be made herein and therefore the invention is not considered limited by that which is shown in the drawing and described in the specification but only as indicated in the appended claims.

What is claimed is: V

l. A roll of elastomeric thermoplastic material of extremely thin gauge and having high cling characteristics which may be dispensed in predetermined lengths, said roll including a core, said roll of material being provided with a transverse slit extending through the convolutions thereof, said slit extending from a point adjacent one free edge of said roll of material to a point adjacent the other free edge thereof and providing a relatively narrow uncut portion at each extremity thereof only, said slit being substantially parallel to the axis of the core, the free edge of said material having the corners thereof which overlie the uncut portion of the roll tufted so as to project outwardly and permit convenient grasping thereof for detachment of a predetermined length of material from said roll, each detaching operation at a transverse slit resulting in the tufting of the corners of the free edge of the next successive length.

2. A roll of elastomeric thermoplastic material as set forth in claim 1 where the material is of a thickness from about 0.00025 to about 0.0015 of an inch.

3. A roll of elastomeric thermoplastic material as set forth in claim 1 where the slit extends through the core.

4. A roll of elastomeric thermoplastic material as set forth in claim 1 where the transverse slit extends to about /8" from each longitudinal edge of the material.

5. A roll of elastomeric material as set forth in claim 4 where the material is of a thickness on the order of from about 0.00025 to'about 0.0015 of an inch.

I References Cited in the file of this patent UNITED STATES PATENTS 401,233 Wheeler Apr. 9, 1889 

1. A ROLL OF ELASTOMERIC THERMOPLASTIC MATERIAL OF EXTREMELY THIN GUAGE AND HAVING HIGH CLING CHARACTERISTICS WHICH MAY BE DISPENSED IN PREDETERMINED LENGTHS, SAID ROLL INCLUDING A CORE, SAID ROLL OF MATERIAL BEING PROVIDED WITH A TRANSVERSE SLIT EXTENDING THROUGH THE CONVOLUTIONS THEREOF, SAID SLIT EXTENDING FROM A POINT ADJACENT ONE FREE EDGE OF SAID ROLL OF MATERIAL TO A POINT ADJACENT THE OTHER FREE EDGE THEREOF AND PROVIDING A RELATIVELY NARROW UNCUT PORTION AT EACH EXTREMITY THEREOF ONLY, SAID SLIT BEING SUBSTANTIALLY PARALLEL TO THE AXIS OF THE CORE, THE FREE EDGE OF SAID MATERIAL HAVING THE CORNERS THEREOF WITH OVERLIE THE UNCUT PORTION OF THE ROLL TUFTED SO AS TO PROJECT OUTWARDLY AND PERMIT CONVENIENT GRASPING THEREOF FOR DETACHMENT OF A PREDETERMINED LENGTH OF MATERIAL FROM SAID ROLL, EACH DETACHING OPERATION AT A TRANSVERSE SLIT RESULTING IN THE TUFTING OF THE CORNERS OF THE FREE EDGE OF THE NEXT SUCCESSIVE LENGTH. 